"New Concepts in Octane Boosting of Fuel for Internal Combustion Engines"
Dr. Paul Waters, American University, Department of Chemistry to the
American Chemical Society, August 2000

The holy grail of the process of the combustion of fuels in
internal combustion engines is the perfect mixture of fuel and air. This ideal
state is to provide complete combustion at a uniform rate, to deliver optimal
power with no pollution of the atmosphere. A primary objective of engine
builders is to provide the engine designs that will produce a uniform
distribution of fine diameter fuel droplets deemed crucial to forming a mixture
approaching perfection. When high molecular weight polymers are added to
hydrocarbon fuels at low ppm levels, the viscoelasticity manifested during the
stress of carburetion or injection precludes the formation of large numbers of
fine droplets. The average droplet size of such fuels aerosolized in air is 55
microns and the size distribution is narrowed measurably from that of neat
fuels. Such polymer-fortified fuels burn more slowly initially at significantly
lower temperatures, thereby increasing the octane rating of the fuel, the
efficiency of the combustion and the power delivered to the crankshaft.

"Global Warming
Reduction by Polymers in Automotive Fuels" Dr. Paul Waters, American
University, Department of Chemistry to the American Chemical Society, August
2000

When polymers which can impart sufficient viscoelasticity to hydrocarbon (HC)
fuels are introduced with the fuel into the combustion chambers of internal
combustion engines the fuel droplets formed burn more efficiently at lower
temperatures, resulting in lower fuel consumption and greater power. The lower
operating temperatures of the engines mean that less heat is contributed to the
global thermal burden. The greater efficiency of the engines means that a lesser
quantity of carbon dioxide is produced per unit of work provided. The
pollutants: HC, CO and NOx are significantly reduced and this obviates their
prospective greenhouse-warming effects. The contribution is holistic in that the
enhanced efficiency of the combustion process in engines reduces the thermal
output not only from individual vehicles but at the refinery and in the vehicles
which transport fuel, as well.

When high molecular weight polymers are dissolved in hydrocarbon (HC) fuels
they impart a viscoelasticity which is evident when the fuel is subjected to the
sudden stress of the carburetion or injection process. The resulting fuel
droplets have a narrower size distribution and larger average diameters than
those from neat fuels. The paucity of low-and sub-micron size droplets moderates
the high temperature spike exhibited with normal fuels and the NOx emissions are
thereby greatly reduced. Because the surface area per unit mass is reduced, the
rapid chemistry, which depletes the region of oxygen and yields partially
oxidized and/or unburned hydrocarbons and carbon particulates in normal fuels,
is diminished. The polymers, present at low ppm levels, cause the fuel droplets
to burn more slowly initially, and more rapidly, uniformly and efficiently later
thereby significantly reducing the emissions of the monitored pollutants, HC, CO
and NOx.

This paper was presented as slides and discussions only. Presentation not
available.

The purpose of this paper is to describe new fuel additive technology being
marketed by GTAT. The technology offered by GTAT provides significant
opportunity to improve combustion efficiency of engines burning liquid fuels
with consequent improvements in power, fuel economy and reduced emissions. Most
importantly, the technology provides these benefits by low cost modifications to
the fuel rather than relatively high cost modifications to engine design and
control systems. Internal combustion engines, in spite of extensive design work
over many years, are still relatively inefficient in terms of combustion
efficiency. (Scientific American, Improving Automotive Efficiency, December
1994, indicated typical combustion efficiencies of 40% for gasoline automotive
engines).

This paper presents combustion technology information gleaned from
publications of the Society of Automotive Engineers (SAE) presented at a recent
national meeting in Detroit in the Fall of 1995 and provides commentary showing
how GTAT’s fuel additives can be used to help overcome combustion problems
identified by the SAE scientists and engineers. This change in approach to
improving combustion by changing the viscoelastic properties of the fuel is a
paradigm shift which offers significant potential for gasoline and diesel
engines. A synopsis of the selected SAE papers is provided followed by a
discussion of how the fuel additive addresses the combustion efficiency problem
presented in the SAE papers.

Dr. J.E. Peters compared the droplet size distribution of sprays of gasoline
from a standard Bosh port fuel injector into static air with and without Viscon.
Dr. Peters used a laser diffraction technique to measure droplet size at radial
positions from the center line of the spray cone 10 cm below the tip of the
injector nozzle.

To evaluate the validity of GTA's claims, a CFR engine was used. In order to
get a reliable baseline, the engine was completely rebuilt. They were able to
obtain peak cycle pressure, brake specific fuel consumption, spark advance
allowed before knock, and maximum brake torque. Unfortunately the Yanmar diesel
engine was not ready, so no data of how the additive effects diesel performance
could be evaluated. The Horiba gas analyzer was not interfacing with the
computer at the time of testing, so no emissions tests could be performed.

The objectives of the study were to determine the effects of a combustion
chamber cleaning additive on octane requirement increase (ORI) and engine
operating, combustion and knocking characteristics as deposits build up over
time and to interpret the observed phenomenon.

The experimenters concluded among other things: "There is a strong
correlation of ORI with unburned gas temperature, regardless of how the deposit
is generated. A rise of TK in unburned gas temperature during combustion (at 10o
ATC) correlates to approximately a one octane number rise in octane
requirement."

Paper available through the American Chemical Society and the Massachusetts
Institute of Technology.

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